The present invention relates to a semiconductor bonding method for bonding a semiconductor chip such as an IC to a substrate, in a face-down manner, and more specifically to a bonding method capable of detecting an error in terms of position, between an electrode of a semiconductor chip and a wiring line provided on a substrate, after a face-down bonding, by inspecting it from outside, and a device therefor.
As one of the methods for directly mounting and bonding a semiconductor chip such as an IC to a mount substrate such as a print wiring substrate, there is a method in which a surface in which the electrode (bump electrode) of a semiconductor chip is formed is made to face a substrate, and the electrode is directly bonded to the wiring pattern of the substrate. This method is generally called "face-down bonding" since the bonding operation is carried out while holding the surface of the semiconductor chip on which the electrode is formed facing downwards.
In the face-down bonding as above, the joint portion between the electrode and the circuit pattern is covered by the semiconductor chip, and therefore it is difficult to confirm if the bonding has been accurately carried out.
In order to detect whether or not bonding has been accurately carried out, that is, to inspect the accuracy of bonding, the method in which the status of the joint portion between the electrode and circuit pattern is physically observed so as to judge if the bonding is good or no good, is generally employed.
More specifically, there is a method in which a semiconductor device which has been subjected to the face-down bonding is sampled at a certain period, and the semiconductor chip is stripped off or cut from the substrate so as to inspect the joint portion of the electrode, and a method in which the joint portion between the electrode and the circuit pattern is examined from a rear side of the substrate transparently.
The method which involves stripping or cutting the semiconductor chip requires the transfer of a sampled semiconductor chip to a separate device, where the stripping and cutting is carried out, the entire system thereby becoming large in size. Further, the inspection cannot be conducted at real time during the bonding operation.
Further, with the transparent inspection method, it is not possible to obtain a clear image of the joint portion, and therefore an accurate inspection cannot be conducted. More specifically, for example, a ceramic substrate or glass substrate is used as the substrate, and particularly, in the case of the ceramic substrate, the amount of light transmission is very small. As a result, it is very difficult to confirm even the outline of a semiconductor chip, not to mention the joint portion between the electrode and circuit pattern.
Further, in the case where a semiconductor chip is face-down bonded to a glass substrate, it is difficult to obtain a clear image of the joint portion between the electrode and circuit pattern due to the state of the refraction of the glass substrate or the presence of the circuit pattern, although the outline of the semiconductor chip can be traced.